Ord 1.] TETRANDRIA MONOGYNIA. 31 



81. POTAMOGeTON. Pet. 4. Cal. 0. Seeds 4, naked, sessile. 



— N.O. Naiades. 



82. RuPPIA. Pet. 0. Cal. 0. Seeds 4, stalked N.O. Naiades. 



Cerastium. 



TETRANDRIA MONOGYNIA. 



Go. DlPSACUS. Teasel. 



1. D. fullonum, 29. 2080. (Fuller's T.) Leaves combined, ser- 



rated. Scales of the receptacle hooked backwards. Common 

 calyx reflexed. 

 Hedges, not wild. $ . 7. Erect, 5 or 6 f., prickly. Fl. whitish. 



2. D. sylvestris, 15. 1032. (Wild T.) Leaves opposite, serrated. Scales 



of the receptacle straight. Common calyx inflexed, longer than 

 the head. 

 About hedges. $ . 7. Less robust, 4f. Scales taper, less rigid. 



3. D. pilosus, 13. 877. (Small T.) Leaves stalked, with lateral 



leaflets. Common calyx deflexed, about the length of the head. 

 Moist chalky soil. If. 8. L. ovate, pointed. Fl. white. Scales/ringed. 



66. SCABIoSA. Scabious. 



1. S. succisa, 13. 878. (Devil's-bit S.) Corolla in four equal seg- 



ments. Heads nearly globular. Stem-leaves distantly toothed. 

 Past. If. S — 10. R. abrupt. Stem 1 — 2 f., hairy. L. entire. Fl.blue. 



2. S. arvensis, 10. 659. (Field S.) Corolla in four segments; themar- 



ginal flowers radiant. Leaves pinnatifid, cut. Stem bristly. 

 Fields. If. 7. Root tapering. Stem 3 f. Fl. large, pale purple. 



3. S. columbaria, 19. 1311. (Small S.) Corolla in five unequal seg- 



ments. Radical leaves ovate, or lyrate, notched ; the others 

 pinnatifid, linear. 

 Moist chalky soil. If- 6, 7. R. woody. Stem 12 — 18 in. Cor. radiant. 



67. SHERARDIA. Field-madder. 



1. Sh. arvensis, 13. 891. (Little F.) Leaves all whorled. Flowers 

 terminal. 

 Fields. 0.5 — 8. Spreading. 3 — 6 in. L. obov. Cor. purplish blue. 



68. ASPeRULA. Woodruff. 



1. A. odordta, 11. 755. (Sweet W.) Leaves eight in a whorl, 



lanceolate. Panicles stalked, of few flowers. 

 Woody mount. If . 5. L. shining, rough attheedges. Fl.pure white. 



2. A. cyndnchica, 1. 33. (Small W. Quinsy-wort.) Leaves linear, 



four in a whorl ; the upper ones very unequal. Flowers all four- 

 cleft. Fruit smooth. 

 Dry chalky banks. If . 6. Spreading. 4 — 6 in. Cor. flesh-col. 

 *3. A. arvensis, Suppl. 2792. (Field W.) Leaves 6 — 10 in a whorl, 

 linear-lanceolate, obtuse. Flowers aggregate, terminal, sur- 



